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April 1: A Full Pink Moon and a double star
You’ll want eyes on Jupiter this evening as Europa passes north of Callisto while Ganymede’s large shadow transits the gas giant’s cloud tops. Start observing by 11 P.M. EDT, as the bright planet hangs in the west beneath the heads of Gemini the Twins: Castor and Pollux.
At that time, Ganymede’s shadow is already crossing the cloud tops, having begun its journey an hour before (so feel free to start watching then, if you’re able!). Ganymede itself lies west of the planet, with Io farther west. On the eastern side of Jupiter, Europa and Callisto are close to each other, with Europa just east of Callisto. This is where you’ll want to watch: Both are moving westward, toward the planet, but Europa is moving faster. At 11:30 P.M. EDT, the smaller moon moves due north of Callisto, with the two 7” apart. After that, Europa will overtake its fellow moon, moving closer to Jupiter as Callisto falls behind.
Ganymede’s shadow transit continues as well, ending shortly after 1:22 A.M. EDT, now April 3 for the eastern half of the U.S. — where the view is also diminished due to Jupiter’s low position. The western half of the U.S. gets the better view as Ganymede’s shadow reaches Jupiter’s western limb and disappears.
Sunrise: 6:42 A.M.
Sunset: 7:26 P.M.
Moonrise: 8:24 P.M.
Moonset: 6:41 A.M.
Moon Phase: Waning gibbous (99%)
*Times for sunrise, sunset, moonrise, and moonset are given in local time from 40° N 90° W. The Moon’s illumination is given at 10 P.M. local time from the same location.
Mercury is now visible in the early-morning sky. The planet reaches greatest western elongation, standing 28° from the Sun, at 7 P.M. EDT on April 3. Before then, though, you can catch it before dawn.
The small planet glows at magnitude 0.4 and rises around 5:45 A.M. local daylight time. That doesn’t afford much time to see it, but early risers can spot it some 4° above the eastern horizon about half an hour before the Sun rises. Mercury is now in Aquarius and currently tracking eastward, or prograde, against the background stars.
Through a telescope, the planet’s disk spans 8” on the sky. It is roughly half-lit (49 percent) and its illumination will increase in the coming days as Mercury remains at roughly the same altitude above the horizon, while Mars and Saturn slowly rise to meet it in the morning sky. Currently, Mars is above the horizon half an hour before sunrise, but just barely — the Red Planet stands just 1° high at this time and is very faint at magnitude 1.3. You can try looking for it in binoculars or a telescope 9.1° northeast of Mercury (to Mercury’s lower left), but you will need a very clear horizon free of trees or buildings. Take care to put away any optics well before sunrise from your location, which may differ from the time given below.
